I suspect this issue could have the same cause as whatever is stopping Euphoria from working properly. The problem is that if you have multiple consecutive notes on a simpledrums track, only the first note (sample) in any block of consecutive notes gets played.
Within the simpledrums window between the channel on/off and note on/off check boxes there are supposed 'Volume' buttons that don't do anything. I think they should be rotary dials but they're not.
There is a unneeded slider on the right that doesn't slide anything.
Under the Synth -> MESS window it is called SimpleSynth but its 'about' button says its called SimpleDrums which I think is a better name.
I think it'd be better renamed to SimpleDrums in the menus as I think its misleading to call it a 'synth'.